It is known to use simulated joints, particularly for test purposes. For example, a dummy may be carried in a test sled or vehicle and the vehicle may be advanced against an obstruction to simulate a crash. In testing, a dummy leg may, for example, be employed. The simulated knee joint should have a resistance comparable to that of a real knee joint to enhance its utility in the tests and to afford insight into the response of a human joint in real crashes.
Heretofore, a simple joint has been used which displays a frictional resistance to flexure. The frictional force may be adjustable. Nevertheless, there are difficulties involved in the use of frictional joints. Repeatability of setting is difficult. The frictional forces resisting the flexure cannot be programmed variably with time in a desired manner, but are dependent on initial settings. Wear gives rise to non-repeatable settings and to nonuniformity. Such frictional joints are velocity sensitive and exhibit torque spiking at the static-kinetic transition. The frictional joint also makes it difficult to fix the dummy in position in the sled or vehicle.